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1. Field of the Invention
The present invention is directed to management, testing and maintenance of cellular telephone systems. More particularly, the present invention is directed to a system and method for remotely initiating the monitoring of cellular telephone call parameters and displaying those parameters in a dynamic graphical form in real or near real time.
2. Background of the Invention
Unfettered mobile telephone network access, call continuity and call clarity are some of the technical considerations that are continually optimized to achieve a high level of mobile cellular telephone service. In order to achieve improved performance levels, cellular telephone service providers must, among other things, position antennas in geographically desirable locations and tune and/or direct the antennas in optimal ways. While radio frequency (RF) engineering tools exist to help properly position individual cellular telephone cell site antennas and configure overall cellular systems, the only effective way of actually determining whether the cellular antennas and their tuning/positioning have been properly accomplished is to perform field tests with a cellular telephone. Typically, such field tests are accomplished with xe2x80x9cdrive testsxe2x80x9d wherein an RF or cellular engineer drives a vehicle around in a designated area while making one or more telephone calls using his cellular telephone. During the drive test, the RF engineer monitors call performance by noting call drops, for example, and/or collecting actual downlink data such as signal strength directly from the mobile telephone. Test equipment for the performing such tests is manufactured by, for example, X-Tel, Comarco and LCC.
The RF engineer then returns to his office where he uploads the collected data to, e.g., a computer spread sheet program, and attempts to combine or correlate this data with data, from the same time period as the drive test, obtained from the cellular system""s controller or switch, i.e., a Mobile Telephone Switching Office (MTSO) or Mobile Switching Center (MSC). The data from the switch might include signal strength, Bit Error Rate (BER) and other call events, such as call handoffs, during the time that the RF engineer was performing the drive test.
Once an analysis of the combined data is complete and changes to the cellular system are made (if necessary), the RF engineer will typically return to the drive test area for another drive test to confirm that the changes made have improved overall system performance. The iterative procedure of drive testing, system changing, and subsequent drive test confirmation continues as long as cellular system subscribers (users) complain about inadequate service or it is believed that improved service, e.g., coverage and continuity, can be achieved.
While the drive test is an effective method of confirming and testing system performance, it is also an extremely wasteful exercise, in terms of time, for an RF engineer. Instead of spending valuable time making calculations and studying data to optimize a cellular system in an office setting, the RF engineer might spend half or even up to two thirds of his day driving to, around and from an area under investigation. This drive test time factor is even more pronounced if the RF engineer must travel to a rural area to investigate customer complaints and/or perform routine system checks. Thus, the drive testing conventionally employed to monitor and upgrade a cellular system""s performance wastes an RF engineer""s valuable time.
Additionally, the data that is collected from the mobile telephone and switch is often rather xe2x80x9ccrypticxe2x80x9d as illustrated in FIG. 1. Specifically, while individual parameters such as signal strength, BER, etc. are recorded over time by the switch (and where possible, by the mobile telephone itself), these parameters are output from the switch (and/or mobile telephone) as numeric or text data, which is difficult to understand unless one has extensive knowledge of the various codes and formats employed. FIG. 1 shows a typical feed of data from a switch. This difficulty is compounded by the fact that cellular system providers often deploy switches from different manufactures, e.g., Hughes, Lucent or Ericsson, and each of these manufacturers provides call information data in different formats and in different orders. This makes it particularly difficult to fully appreciate the data that is available, let alone to properly correlate the call information data from the switch with the mobile telephone data, if any, for analysis.
To overcome the deficiencies in the conventional methods described above, the present invention provides a system and method whereby the RF engineer need not himself conduct a drive test. Instead, someone else can perform the drive test while the RF engineer remotely accesses the Mobile Telephone Switching Office (MTSO) or Mobile Switching Center (MSC) (xe2x80x9cthe switchxe2x80x9d), places the switch in a call monitor mode and captures telephone call information from both the switch and the mobile telephone (when the cellular system is a digital system) without ever having to leave his office. The present invention further provides a single, easy to follow, graphical presentation of the captured call information even though the switches or mobile telephone manufacturer""s equipment from which the call monitor information is obtained might vary.
More specifically, the present invention comprises an executable program that runs on a computer, e.g., a personal computer (PC). The PC preferably includes a modem or other communications link whereby the PC can dial up the switch, issue commands to the switch to cause the switch to collect or capture call information for a particular Mobile Identification Number (MIN), and download that call information to the PC.
Upon receipt of the call information, the executable program parses the call information, depending on the format and order of the call information received in accordance with switch type that has been accessed, converts and/or scales the call information as necessary, loads the data stored into a file using a standard file format, and then graphically displays the data stored in the file, wherein the displayed data dynamically changes as new call information data is received.
Preferably, the standard file format includes a mobile service subscriber""s number, e.g., a mobile identification number (MIN), the cell site that is presently serving the mobile phone, the channel that is being used, forward and reverse signal strengths, and forward and reverse bit error rates.
The standard file format preferably also includes the reverse signal strength at several other cell sites, and most preferably up to 24 cell site neighbors that are in close proximity to the serving cell, in accordance with the digital EIA/TIA 136 specification.
The data stored in the standard file format is then displayed using a graphical user interface including a graphical representation of the data along with alphanumeric information. That is, the retrieved data is displayed in a graphical, dynamic format on a computer display for the user to analyze.
With the present invention, the RF or cellular engineer no longer needs, himself, to conduct drive tests. Rather, a driver other than the RF engineer can be sent to conduct a drive test while the RF engineer remotely monitors the call from his office.
It is therefore an object of the present invention to provide a real time call monitoring system and method that captures, from a switch, in real or near real time call performance information.
It is another object of the present invention to reformat the captured call performance information into a standard format that can be used for all switch types.
It is yet another object of the present invention to provide a real time call monitoring system and method that dynamically displays call performance information as it is received.
It is another object of the present invention to remotely access a cellular switch and cause it to record and send call performance information for a particular mobile telephone call.
It is also an object of the present invention to provide a real time call monitoring system and method wherein persons other than RF engineers perform cellular system drive tests.
It is a further object of the present invention to provide a real time call monitoring system and method that provides a single graphical user interface for call performance information that is obtained from switches having different manufacturers and thus different formats.
These and other objects of the present invention will become apparent upon a reading of the following detailed description in conjunction with the accompanying drawings.